This is the third such attack on US forces in Iraq over the past week. On Sunday, three rockets targeted a US camp in Diwaniyah, a city south of the capital Baghdad.
In August 2010, the United States declared an end to its combat mandate in Iraq but left 50,000 of American troops in the country for what it called "advising and training" purposes.
The United States and its allies invaded Iraq in 2003, citing concerns over alleged weapons of mass destruction wielded by the executed Iraqi dictator Saddam Hussein's Ba'athist government.
No such weapons were ever found in Iraq. However, nearly 50,000 American troops still remain in the country.
The US forces, however, are expected to fully withdraw from the Iraqi soil by the end of 2011 despite a recent plea by US Secretary of Defense Robert Gates for further extension of their troop's deployment in the war-torn country.
American troop presence in Iraq is widely unpopular in the country. Iraqi politicians were quick to reject the American request for a longer stay of its forces.